Punchers are used to punch holes in paper and other sheet materials, such as cardboard, leather, fabric, plastics, and similar materials, usually in order to be able to bind these sheets in a binder. There are several different binder standards. The most popular in the US are the three-hole binders where the distance between two adjacent rings is 4.25″ and the two-hole binders where the distance between binder rings is 2.75″.
Numerous adjustable punchers are known to the art where the punching members are readjusted in order to switch from a three-hole punch to two-hole punch, and vice-versa. For example, in the U.S. Pat. No. 2,534,094, J. A. Yerkes discloses an adjustable paper puncher where 11 removable punch members can be inserted into all or any of the available 11 holes. In this puncher, a switching from two to three holes requires a readjustment by pulling and reinserting of the punch members.
In the U.S. Pat. No. 4,724,734, Park-Son Hse discloses a multipurpose puncher that includes a pair of one-hole stationary puncher assemblies positioned separately on a base, and a movable puncher assembly mounted slidably between these stationary assemblies. This puncher permits to switch from a single-hole punch and a two-hole punch without making any changes to a puncher. But switching from a two-hole to three-hole punch requires a readjustment.
In the U.S. Pat. No. 5,829,334, Alfred J. Evans and Balaji Kandasamy disclose another adjustable paper puncher where the switching from two to three holes requires a readjustment from the bottom of the punch by sliding the punching heads to the required punching positions.
Placing two separate punchers, a two-hole and a three-hole puncher, side-by-side on the same platform has never made any sense because such a dual purpose unit would take as much space on the desk as two separate units.